1. Field of The Invention
The invention concerns an implantable electrostimulation device, for example a pacemaker or defibrillator, with a top portion for the electrical connection of an electrode lead with a fixedly installed connecting socket and the inside wall of the fixedly installed connecting socket having radially inward pointing contact and holding means for engaging an electrode lead contact.
The invention further is directed to an electrode lead for an implantable electrostimulation device with a pin or annular contact for inserting into a connecting socket of the electrostimulation device.
2. Description of the Related Art.
From DE-A-3 311 510, an arrangement is known for connecting the proximal end of a bipolar electrode lead to a pacemaker, wherein the electrode lead has a front pin contact and an annular contact being disposed in distal direction behind it. For the connection to the pacemaker, the proximal pin contacts for the electrode lead are inserted into a hollow cylindrical, so-called end block where they are secured in place with a screw. The locking screw in the end block is designed to ensure a sufficient electrical contact on the one hand, and on the other hand is designed to provide protection against an undesired axial displacement of the lead contact within the end block, so that the proximal end of the bipolar electrode lead cannot detach itself from the pacemaker. The second connection for the electrode lead, which is provided in distal direction behind the pin contact and is designed as annular contact, is inserted into a sleeve with three notches on its inside surface in order to make contact. A wire that is essentially bent into a circle is inserted under mechanical prestressing into these notches in such a way that the annular contact is electrically connected at three points with the wire, provided the pin contact for the electrode lead is in the end block designed for it.
This solution has the disadvantage that the screw-connection and the use of a wire that is essentially bent into a circle and inserted into a sleeve does not ensure a large-surface contacting and in addition only provides insufficient security against an unintended disconnecting of the connection during an axial stressing of the electrode lead.
In U.S. Pat. No. 4, 583, 543, an arrangement for connecting a bipolar electrode lead to a pacemaker is suggested where in order to connect an electrode lead that is thinner than the originally planned one, an adapter is provided in the top portion of the pacemaker. The connection between the adapter and the electrode lead is a frictional connection that is created as a result of a multiple contact that essentially occurs only at contact points along a single circumferential line of contact for the electrode lead. The safety against a loosening of the connection during an axial stressing of the electrode lead appears to be insufficient.
EP-A-0 339 877 furthermore discloses a connector system for pacemakers, which provides in the top portion of the pacemaker two metal cylinders with inside-positioned spring wires for contacting the electrode lead connections. The safety against a disconnecting of the electrical connection between electrode lead and pacemaker during a mechanical stressing in axial direction is insufficient in this case as well, since this is countered only by a frictional connection in essentially linear contact regions.